Plug and receptacle



v Aug. 23, 1938. T. E. MODOWELl.

PLUG AND RECEPTACLE Filed May 24, 1957 3 She ets-Sheet 1 Aug. 23, 1938.- 'r. E. McpowELL.

PLUG AND RECEPTACLE- Filed May 24, 1957 3 Sheets-Sheet 2 Au 23, 1938, T, E, MCDO ELL 2,127,928

PLUG AND RECEPTACLE Filed May 24, 1957 3 Sheets-Sheet 3 ZWMEUUH Patented Aug. 23, 1938 UNITED STATES PATENT OFFICE PLUG AND RECEPTACLE Application May 24, 1937, Serial No. 144,452

3 Claims.

The present invention relates to plug and receptacle construction, and more particularly to improvements in electrical connectors and more particularly to two-part separable connectors of the plural contact type, wherein the parts are connected and disconnected by axial movement of the parts towards and away from each other.

An object of the present invention is to provide a two-part electrical connector wherein the insulating bodies carrying the male and female contacts may be interchangeably assembled in the protective casings of the parts.

Another object of the invention is to provide a two-part electrical connector in which the insulating contact carrying bodies are formed each of two members, with the bodies secured in place in their protective casings by connecting means between the two members of a body.

A further object of the present invention is to provide a two-part electrical connector wherein the insulating contact carrying bodies are fashioned each of two members, and wherein the two members of a body are clamped about a portion of its casing to prevent separation of the casing and body.

A still further object of the present invention is to form an insulating body for one part of a two-part separable electrical connector, which body consists of two members, one of which members carries the contacts for said one part, and the other of said members is restrained against displacement with respect to its casing by making shouldered engagement with said casing, and securing said two members together within the casing to clamp them to the shoulder to prevent displacement.

The invention has for a further object the provision of a two-part electrical connector construction wherein the insulating bodies of the parts are clamped in place within their protective casings by cooperating parts of the bodies and casings.

The invention has for another object the provision of a two-part electrical connector construction wherein the insulating bodies for the parts are held in place in their protective casings by bolts which do not threadedly engage any part of the casings.

The above, other, and further objects of the present invention will be apparent from the following description and accompanying drawings.

The accompanying drawings illustrate a twopart separable electrical connector, constructed in accordance with the principles of the present invention, and the views thereof are as follows;

Figure l is an elevational view of a separable tional view through one part of the connector,

herein designated as the receptacle.

Figure 3 is an enlarged, fragmental, axial sectional view through the other part of the connector of the present invention, herein designated as the plug.

Figure 4 is an end view of a receptacle of Figure 2, looking at the right-hand end of Figure 2.

Figure 5 is a transverse section taken substantially in the plane indicated by line V-V of Figure 2.

Figure 6 is an exploded view showing a fragmental portion of a protective casing, and the members constituting the insulating bodies of the present invention, the parts being in proper position for assembly of the body members in their protective casing.

Figure 7 is a transverse sectional view taken substantially in the plane indicated by line VII-VII of Figure 2.

Figure 8 is an axial central view of one of the protective casings of the illustrated form of the present invention.

Figure 9 is an end view of the casing of Figure 8, looking at the right-hand end of said figure.

Figure 10 is a transverse sectional view taken substantially in the plane indicated by the line XX of Figure 8.

The drawings will now be explained.

The two-part separable connector illustrated in Figure 1 includes a receptacle A and a plug B.

The receptacle A has a protective casing I of the general form and shape illustrated in Figures 8, 9, and 10 and is made of suitable material, such for example as Bakelite or any other material suitable for the purpose.

The casings of both the receptacle A and the plug B are similar in shape and form and are adapted to interchangeably receive the insulating bodies of the plug and receptacle.

Figure 8 illustrates the details of the illustrated form of casing which is made of generally cylindrical form in end elevation, having its rear por tion of reduced diameter with respect to the front portion. The rear portion is shown at the left in Figure 8, and the front portion is shown at the right in Figure 8.

The extremity of the reduced rear portion is threaded at 2 and the entrance end to the rear portion is preferably formed with a frustroconical surface 3 against which the irustroconical outer surface of a bushing 4 bears when the parts are assembled. For retaining the bushing 4 in position, a strain relief nut 5 having an end wall 6 in which there is the central opening I of less diameter than the internal threads of the nut, is threaded on to the threaded portion 2 of the casing and carries a washer 8 which bears against the bushing 4. When the electrical cables G are passed into the ends of the rear portions of the casings, and are suitably connected to the contacts carried by the insulating bodies, and the body parts are assembled in operative relationship, the nuts 5 are tightened to thereby compress the bushings 4 about the conductors to prevent withdrawal of the cables, and serve as strain relief means for the cables.

The casing l is formed with an internal annular shoulder 9, at substantially the junction between the rear and front parts. A portion of the surface of the interior of the casing is cut away to form an arcuate recess ID the bottom or inner surface of which is spaced inwardly from the shoulder 9. This recess I serves as an arcuate slot in which a tail piece on the inner member of the insulating body works, to limit rotative movement of said inner body, as will be hereinafter more fully explained.

The interior of the casing, at its front end is fashioned to provide a plurality of inwardly directed axially extending tongues ll, l2, and i3. Between the tongues, circumferentially of the casing, are arcuately shaped grooves I4, I53, and Is. As illustrated, the groove M is between the tongues H and I2, the groove l between the tongues l2 and I3, and the groove l6 between the tongues 13 and H. The inner extremities of the tongues ll, [2, and I3 stop short of the annular shoulder 8, within the casing, a distance but slightly greater than the axial thickness of a part of an inner member of the insulating body. The inner extremities of the several tongues, constitute what are herein termed as shoulders and are designated at I! in Figure 8.

In order to prevent assembly of an insulating body in its casing in any but the proper relative angular relationship, the circumferential extent of the several grooves as well as the intervening tongues, are different. As illustrated, the circumferential extent of the grooves l5 and. I6 is the same, while the circumferential extent of the groove I4 is greater than that of either of the grooves I5 and 16. The circumferential extent of the tongue I3 is greater than the circumferential extent of either of the tongues H and I2, the tongues H and I2 being of the same circumferential extent.

If desired for ease of assembly of the insulating body members in their casing, one of the tongues, such for example as the tongues l3 may be provided with an axially extending notch l8.

When the tongues H are provided with axially extending notches l8, the body members C and D may be provided with projections 62 to interfit with said notches during assembly of these parts in the shell.

Immediately in front of the annular shoulder 9 the interior of the front end of the casing is cylindrical, with a diameter of that of the bases of the several grooves l4, l5, and i5 formed in the front end of the casing.

The insulating body for the receptacle A is formed of two members C and D, which are illustrated in axial section in Figure 2, and in isometric view in Figure 6.

Likewise the insulating body for the plug B comprises two members, C and the member C being of the same construction for both the receptacle A and the plug B.

The member C, herein termed the inner member is of less axial length than either of the outer members D or E of the insulating bodies. Each of the inner members C is formed with radially projecting tongues 69, 2t, and 25 which are circumferentially spaced by axially extending grooves 22, 23, and 2d. The groove 22 is between the tongues l9 and M, the groove 23 is between the tongues 2D and 2!, and the groove 24 is between the tongues 2i and ill. The circumferential extent of the tongue 2! of the inner member C is fashioned to slide into the groove M of the casing i. In like manner the tongue l9 of the member C fits the groove 56 of the casing, and the tongue 20 fits the groove 85 of the casing. The grooves 252, 23, and 24 of an inner member C receives, respectively, tongues l3, l2, and H of the casing when the inner member C is assembled in its casing. Referring to Figure 6 of the drawings, the face of the inner member C which. is readily observed, is for convenience herein termed the outer face. The inner face of each of the inner members C is provided with an axially extending lug 25 which, when an inner member is assembled in its casing, lies within the recess iii of the casing. The relationship of the lug 25 and the inner face of an inner member C, is such that when an inner member is assembled in its easing by axial movement, the lug will lie against the left-hand end of the recess If), as viewed in Figure 10.

The outer face of each of the inner members C is provided with outstanding collars 25. there being as many of these collars 26 as there are apertures 2'6 through the inner members for passage of conductors to the contact members carried by the outer insulating member of a body. Each of the insulating bodies C is provided with axially extending, circumferentially spaced apertures 28 which are arranged between the several collars 26 and conductor apertures 27 of the member C, for receiving attaching bolts 29.

Preferably the insulating bodies C, D, and E are made of moldable material, such for example as Bakelite, or other material of suitable nature. At the time the members C are molded, metallic inserts or bushings 3B are molded with the members. The interiors of these inserts 3?! are threaded to receive the threaded ends 3| of the bolts 29. The rear face of each of the members C is formed with circular projections E32 formed as continuations of the apertures 23 of the member C, to serve as feet to bottom against the shoulder 9 of the casing when a member C is assembled, as may be readily observed in Figures 2 and 3.

The relationship of the conductor apertures 21 in the inner member C, with respect to the relationship of the apertures 32 of the outer member D of the receptacle insulating body, is such that when the inner and outer members C and D, are aligned for assembly in a receptacle casing l, as illustrated in Figure 6, the apertures 21 and 32 are out of axial alignment.

The inner members C are assembled in their casings by applying these members to the front ends of the casings, with the tongues and grooves in interfitting relation, and sliding the members C inwardly until the same abut the shoulders 9 of the casings, thereupon the inner members C are given rotative movement clockwise as viewed in Figure 6, and counterclockwise as viewed in Figure 5, until the lugs 25 abut the right-hand extremities of the recesses H), as viewed in Figure 10, which movement brings the tongue 2| of an inner member C under the shoulder ll of a tongue H of the casing, the tongue l9 of the member C under the corresponding shoulder ll of the tongue I3 of the casing, and the tongue 20 under the shoulder I! of the tongue I2 of the casing, thereby interlocking the inner members in the casings against axial displacement.

The inner members C are rotated so that the lugs 25 thereof rest against the right-hand extremities of the recesses IU of the casings as viewed in Figure 10, the conductor openings 21 are then in alignment with the openings 32 of the outer members of the insulating bodies.

The member D, of the insulating body for receptacle A is likewise formed of moldable material, such for example as Bakelite, and in general the surface contour is cylindrical. Formed in the body D, when it is molded, are the contact openings 32, which are angularly spaced and which extend throughout the length of the mem ber D. In the outer surface of the inner end of the outer member D are formed grooves 33, 34, and 35 which, in circumferential extent, are

, adapted to receive the tongues I I, I3, and I2, re-

spectively, of the casing l of the receptacle, as may be observed in Figure 7. The several grooves 33, 34, and 35 extend part way of the length of the outer member D, terminating in circumferential shoulders 36 which, when the outer member D is assembled in its casing, abut the outer ends of the tongues ll, l2, and I3 of the casing I, thereby limiting the assembled or inward position of the outer member D in the casing.

The inner face of the outer member D is shaped to conform with the outer surface of the inner members C, to receive the collars 26 surrounding the conductor apertures 21 of the member C.

The shape and arrangement of one of the contact receiving openings 8 is shown in section in Figure 2.

An opening H is bored from the inner end of the member D, i. e., left hand as shown in the figure, with a series of axially spaced bores 38, 39 and 32, respectively of decreasing diameters in the order shown.

The largest bore 38 receives a collar 26 of the inner member C, when the members are assembled, the intermediate bore 39 receives the enlarged end or head 63 of a female contact F, while spring fingers 44 of the contact lie within the bore 32, which is of greater axial length than either of the bores 38 or 39. There is an entrance 3! to an opening H, for a male contact, which opening is bored through an end wall 43 at the outer end of the member D.

Formed in the insulating member D and disposed between the opening 32 of the member, are apertures 40 for the attaching bolts 29. The apertures 48] extend axially of the member D.

The outer face of the member D is counterbored at 4! to receive the heads 42 of the several bolts 29 and immediately adjacent the counterbores M the body D is apertured and threaded at 64 to engage the threaded ends of the bolts when the bolts are first applied to the member D. Inwardly of the threaded portion 64 the body is bored to provide elongated bolt holes of sufficient diameter to slidingly receive the threaded ends of the bolts 29 and permit easy movement of the bolts lengthwise of the member D. The

purpose of the threaded portions 64 is to prevent loss of the bolts 29 from the member D, when this member is disconnected from the inner body member C. In other words, the bolts 29, when the member D is disconnected from its member C, may slide back and forth in the apertures 43 but cannot fall out of the member because of the fact that the threaded portion of the bolts must be unscrewed through the threaded portions 64 of the member D before the bolts can be removed.

Within the contact openings H of the member D of the receptacle insulating body, are female contact members, designated generally as F. These contact members F are inserted in the body member D through the inner end of such member, that is to say, from left to right, as viewed in Figure 2.

Every one of the female contacts F is provided with split'sleeve portion 44, the outer extremities of which terminate inwardly of the wall 43 defin- I ing the entrance opening 31. The inner portions or heads 63 of the contacts F are, exteriorly, fashioned to fit within the bores 39 and 32 of the contact openings or apertures H, and preferably with extremities 45 which enter slight distances into the collars 26 of the inner member C. The inner ends or heads of the contacts F are counterbored at 43 and into these counterbores are insertedthe ends ll of the individual conductors G. The conductors G of cable are preferably soldered to the contacts F, thus assuring integral connection and proper electrical connection as well.

The outer face of the member D is provided with channels 48 which communicate one with another substantially centrally of the member D, and extends radially outwardly to the counterbores 40 for the bolt heads 42. The purpose of the channels 48 is to prevent such an accumulation of carbon particles, due to arcing, when the parts of the connector are separated, as

would otherwise short-circuit the receptacle insulating body between any two of its contacts F. Thechannels 4B are deep enough, axially of the member D, to prevent carbonization of materials such as Bakelite, created by arcing to prevent short-circuiting, for substantially the life of the member D. s

Figure 4 shows the position of the channels 48 with respect to the contact apertures of the member D.

In wiring the receptacle A, the bodies C and D are removed from the casing, the conductor cable is inserted through the rear end of the casing, and the individual wires of the conductor severally applied to the counterbores 46 of the female contact members F, with these contacts removed from the outer member D. Before the conductors are attached to the contacts F, the wires thereof are passed through the conductor apertures 21 of the member C, which is out of the casing l, during such wiring assembly, and then the contacts F are soldered to the extremities of the conductors and the contacts F are inserted in the openings H of the member D. Member C is then moved along conductors to butt against end of contacts, whereupon the inner body member C is assembled in its casing I by engaging its tongues and grooves with the grooves and tongues, respectively, of the casing, moving the inner member C inwardly until it rests against the shoulder 9, whereupon the member C with contacts is given rotative movement so that its tongues lie under the shoulders ll of the tongues ll, I2, and I3 of the casing I. The member D, is then applied over contacts F by sliding the contacts into the several apertures 32, from the inner end of the body D, as viewed in Figure 2. The outer body member D is then assembled into the casing by sliding it with its tongues entering the grooves l4, l6, and I5 of the casing, and its grooves 33, 34, and 35 receiving the tongues l I, I3, and I2, respectively, of the casing, thus properly aligning the outer member D in the casing. The inner member D is moved into its casing I until the shoulders 36 of its grooves abut the outer extremities of the tongues of the casing, whereupon the bolts 29 are threaded into the bushings 30 of the inner member D and tightened to hold the members C and D together.

By reason of the fact that portions of the inner member C abut the shoulder I! or inner ends of the tongues of the casing and the shoulders 36 of the outer member D abut the outer extremities of the tongues of the casing, then when the bolts are tightened, the inner and outer insulating body members are clamped against the ends of the tongues, thereby interlocking the insulating body in its casing against endwise displacement.

By reason of the fact that the tongues and grooves of the outer member D are in engagement with the corresponding grooves and tongues of the casing, rotative movement of the outer member with respect to the casing is prevented. Because of the fact that the inner member C is bolted to the outer member D, rotative movement of the inner member is thus prevented so that the insulating body of the receptacle is thus securely interlocked in its casing against axial displacement as well as against rotative displacement with respect to the casing, all without any bolts engaging any part of the casing, thereby eliminating need for precision manufacture of the casing in that respect.

Referring now to Figure 3, the outer member E of the plug insulating body has an outer cylindrical surface conforming substantially to the outer diameter of the front end of its casing. The member E is hollow, having a diameter to telescopically receive so much of the outer member D of the receptacle insulating body as projects beyond the front end of its casing.

The inner portion E of the outer body member E of the plug, is adapted to rest against the inner member C of the plug insulating body and its inner face is shaped and fashioned to receive the collars 26 of its inner member C, as may be observed in Figure 3.

The member E is apertured at 49 to receive pin contacts 50, 5 I. There are, of course, as many pin contacts in the plug as there are female contacts F in the receptacle.

Inwardly of the apertures 49 for the pin contacts the body member E is enlarged at 52 to receive enlarged portions 53 of the pin or male contacts and thus prevent displacement of the male contacts when the parts of the connector are separated.

Arranged between the apertures 49 for the male contacts 50, 5|, the inner portion of the member E is provided with axially extending apertures 6| for attaching bolts 54. The member E is counterbored at 55 to receive the heads 56 of the bolts and to permit these heads to lie inwardly of the adjacent portions of the hollow part of the member E, to prevent possibility of short circuiting. Inwardly of the bores 55 the member E is threaded at 51, for a short distance,

with the balance of the apertures 6| of greater diameter, so that the bolts 54 may slide freely within the apertures, when disconnected from the threaded bushings 30 of the member C.

The bolts 54 of the plug part function in the same manner as the bolts 29 of the receptacle part, as heretofore described.

The members C and E, of the plug part, are assembled as follows:

To attach the conductors to the male contacts 50 and 5|, the bolts 54 are disconnected from the inner member C, the outer member E is withdrawn from its casing, the inner member is then rotated sufficiently to be withdrawn from the casing, whereupon the conductor cable G is then inserted thru the rear end of the casing l of the plug B, with the strain relief nut 5, of course, released, and the wires of the conductor cable passed through the apertures 21 in the member C, and soldered to the enlarged portions 53 of the male contacts 50, 5|, which contacts are removed from the outer member E, for the purpose of soldering. After the wires are soldered to the male contacts, the inner member C is moved into its casing I, and given rotative movement to interlock it under the shoulders H of the tongues of its casing in the same manner as described with reference to the inner member C of the receptacle.

The male contacts are then inserted in the member E and the member slid into the casing B until the shoulder 58 abuts the member E, whereupon the bolts 54 are screwed into the bushings 30 of the member C thus securing the members C and E in fixed relationship in the casing.

The outer surface of the inner end E of the member E is fashioned with the grooves corresponding to the tongues II, I2, and iii of the casing, so as to interfit therewith in the same manner as the outer member D of the receptacle insulating body fits its casing. The grooves of the member E terminate in circumferentially extending shoulders 58 which rest against the outer ends of the tongues ll, l3, and I2 of the casing, when the outer member E is assembled.

Thus when the members C and E are assembled in their casing, and the bolts 54 threaded into the bushings 30 of the member C, the members D and E are clamped against the ends of the tongues ll, [2, and I3 of their casing, to thereby prevent axial displacement of the insulating body with respect to its casing. Because of the fact that the grooves 33, 34, and 35 of the member E interlock with the tongues of the casing l, the insulating body is prevented from rotative movement with respect to the casing.

In order to assure connection of the plug B and the receptacle A, in proper polarity, the outer surface of the member D may be provided with a longitudinally extending groove 59 and the interior surface of the hollow portion of the member E with an axially extending ridge 6!! which enters the groove 59 when the parts are connected.

When the parts A and B are connected, as shown in Figure 1, that portion of the member D of the receptacle lies within the hollow portion of the member E of the plug, in telescoping engagement, with the male contacts 55 and 5| entered in the female contacts F to thereby establish electrical connection of the circuit in which such a connector is installed.

The male contacts 5i? and 5! are of known construction, that is split, to act with spring action when moved into the female contacts F. The splitting of the female contacts F causes the split portions to give slightly when the parts are connected, to thereby assure full electrical connec tion between the contacts F and the contacts 50 and H of the plug.

In order to aid in connection and disconnection of .the parts A and B, the outer surfaces of the nuts 5 may be knurled.

The construction of the various parts permits interchange of male and female connections in either housing.

When the plug and receptacle parts A and B are connected, the outer surface thereof is continuous, contains no projections to catch when the connector is dragged over a rough surface, and the frictional engagement between the contact is suflicient to hold the parts together against any but abnormal endwise pull.

By reason of the fact that the circumferential dimensions of the tongues of the casing and the corresponding grooves of the mating insulating body member, are different, it is impossible to assemble the insulating body members in a casing, in any but proper angular relationship.

The invention has been described herein more or less precisely as to details, yet it is to be understood that the invention is not to be limited thereby, as changes may be made in the arrangement and proportion of parts, and equivalents may be substituted, without departing from the spirit and scope of the invention.

The invention is claimed as follows:

1. In an electric coupling of the class described; a shell; two separable insulating body members in said shell carrying a plurality of electric contacts; one or the inner of said body members being axially and then rotatably assem bled in the shell; said shell and member having cooperating tongue and groove means for guiding the member axially and preventing rotative movement of said member until seated in said shell; said shell having an internal seat for said member; said shell and member having cooperating means for limiting rotative movement of said member when seated; the other or outer of said members being axially assembled in said shell; said shell and said outer member having cooperating tongue and groove means for guiding it and preventing relative rotation between it and said shell; said inner member having threaded bushings for receiving securing bolts; securing bolts in the outer of said members; said bushings and bolts being aligned when said inner member is rotated to its limit in one direction; said shell having means constituting a shoulder engageable by said inner member when rotated to its limit in said one direction to prevent axial movement of the inner member away from its seat, the construction being such that when said members are connected together by said bolts axial displacement of the connected members is prevented by engagement of the inner member with said shoulder and rotative movement of the connected members is prevented by the tongue and groove guide means of said shell and said outer body member.

2. A separable electric connector part comprising a shell open at one end, an insulating body within said shell carrying a plurality of electrical contacts, said body consisting of two separable members arranged in tandem in said shell and applicable to and removable from said shell through said open end, said shell having an annular internal seat spaced inwardly from said open end, the inner of said members being assembled in said shell against said seat and rotated a limited amount, said shell and member having cooperating means to limit rotative movement of said member, said inner member having threaded bushings for receiving securing bolts, the outer of said members being assembled by axial movement of said member into said shell and against said inner member, said outer member carrying securing bolts for engagement with said bushings when said inner member is seated and rotated to its limit in said direction, said outer member and shell having cooperating= tongue and groove means for preventing relative rotative movement of said member and shell, the inner ends of said tongues stopping short of said seat to provide stop means for said inner member when seated and rotated to prevent axial movement of said inner member, the construction be ing such that when said two members are connected by said bolts axial displacement is pre vented by engagement of said inner member against the inner ends of said tongues and rotative movement of the two connected members in the shell is prevented by the tongue and groove engagement of said outer member and said shell.

3. A separable electric connector part comprising a shell open at one end, an insulating body within said shell carrying a plurality of electrical contacts, said body consisting of two separable members arranged in tandem in said shell and which members may be applied to and removed from said shell through said open end, said shell having an annular internal seat spaced inwardly from said open end, the inner of said members being assembled in said shell against said seat and rotated a limited amount, said shell and member having cooperating means to limit rotative movement of said member, said inner member having threaded bushings for receiving securing bolts, the outer of said members being assembled by axial movement of said member into said shell and against said inner member, said outer member carrying securing bolts for engagement with said bushings when said inner member is seated and rotated to its limit in said direction, said outer member and shell having cooperating tongue and groove means for preventing relative rotative. movement of said member and said shell, the inner ends of said tongues stopping short of said seat to provide stop means for said inner member when. seated and rotated to prevent axial movement of said inner member, and said outer member having stop means engageable with the outer ends of said tongues to limit inward movement of said outer member, the construction being such that when said two members are connected by said bolts axial displacement is prevented by engagement of said connected members against the ends of said tongues and rotative movement of the two connected members in the shell is prevented by the tongue and groove engagement of said outer member and said shell.

THOMAS E. MCDOWELL. 

